The invention relates to a doctor apparatus for a web forming machine for doctoring a moving surface with the doctor apparatus including a blade, a blade holder to which the blade is adapted, a frame component to which the blade holder is adapted, and a loading element is arranged between the frame component and the blade holder for loading the blade holder and further the blade.
The invention also relates to a blade holder and a method for a web forming machine for doctoring a moving surface.
At present, an apparatus for doctoring a moving surface is known, for example, from publication U.S. Pat. No. 6,942,734. The apparatus includes a frame component to which a blade holder is connected. The blade holder, in turn, has a blade connected thereto. The blade holder is loaded with a loading hose and for the loading hose, on the other hand, a counter force is provided with an opening hose. In other words, the opening hose providing the counter force for the loading hose is used to open the gap between the blade and a roll surface. There are known several corresponding apparatuses in which the gap between a blade and a roll surface is opened by means of an opening hose and closed by means of a loading hose. However, a common problem with the use of these is that the design of the opening hose is restricted, which means that the opening of the gap between the blade and the roll surface is also restricted. An opening hose and a loading hose also substantially complicate the removal of the blade holder from the frame component.
Publication WO 01/25533 proposes a doctor blade holder and a method for using a doctor. In this publication, it is proposed that the counter force for the loading hose is produced with flexible plates. Plates, however, fatigue in the course of time, whereby the apparatus fails to function as planned.